1. Field of the Invention
The present embodiments relate to semiconductor wafer processing equipment tools, and more particularly, methods for depositing material layers with varying gap settings between electrodes.
2. Description of the Related Art
Some semiconductor processing systems may employ plasma when depositing thin films on a substrate in a processing chamber. Generally, the substrate is arranged on a pedestal in the processing chamber. To create the thin film using chemical vapor deposition, one or more precursors are supplied by a showerhead to the processing chamber.
During processing, radio frequency (RF) power may be supplied to the showerhead or to an electrode to create plasma. For example, RF power may be supplied to the electrode embedded in a pedestal platen, which may be made of a non-conducting material such as ceramic. Another conducting portion of the pedestal may be connected to RF ground or another substantially different electrical potential.
When the electrode is excited by the RF power, RF fields are generated between the substrate and the showerhead to create plasma between the wafer and the showerhead. Plasma-enhanced chemical vapor deposition (PECVD) is a type of plasma deposition that is used to deposit thin films from a gas state (i.e., vapor) to a solid state on a substrate such as a wafer. PECVD systems convert a liquid precursor into a vapor precursor, which is delivered to a chamber.
Generally speaking, chambers used to deposit material layers implement settings that are fixed during a time when the material layer is deposited. The settings may include gas supply settings, power levels supplied, pressure settings and temperature settings and relative electrode positioning. As wafer sizes continue to increase however, it has been discovered that more non-uniformities may occur radially across the surface of the substrate. Often, analysis of deposited materials exhibit more uniformities near the wafer edge and sometimes in the center wafer region. Unfortunately, non-uniformities tend to reduce yield, especially near the wafer edge.
It is in this context that inventions arise.